Different morphologies of bismuth sulphide (Bi2S3) nanoparticles (NPs) were synthesized at room temperature using wet chemical method. The properties of bismuth sulphide (Bi2S3) nanoparticles can be controlled by different amounts of Mn2+ dopant. The synthesized nanoparticles were characterized by several techniques, such as high resolution scanning electron microscopy (HR-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), and energy dispersive X-ray spectroscopy (EDS). The nanoparticles (Bi2S3) were found to have excellent activity for the UV light assisted decolorization of methyl violet dye and also helped to speed up the redox reaction of